Does winter weather predict summer weather? Not so fast
Sunday, February 25, 2018, 8:51 AM - I am often asked about the saying that a harsh cold winter means a great summer. Many people can recall years when that has proven to be true.
So, is there really any validity to this idea?
The best way to answer this question is to look back at some memorable winters and see what the following summers were like.
We will start off with the winter of 2013-2014. This is the year that the “polar vortex” became a buzz word. The map below shows that most of Canada was colder than normal (as indicated by the various shades of blue and purple which indicate colder than normal temperatures for the winter season).
So, what was the following summer like? Did most of Canada have a warm summer? The map below shows that western Canada and Atlantic Canada did have a very warm summer (indicated by the green and yellow colours on the map) but the Great Lakes region had a colder than normal summer (indicated by the blue colours).
So, for part of Canada the saying appeared to work, but parts of Canada it did not. One cannot make any valid conclusions based on just one example, but the contradicting outcomes are problematic. So we will look at a couple more examples.
Let’s go back a few decades to two of the more legendary winters. The map below is from the winter of 1977-1978, which was a very cold winter from British Columbia to southern Quebec.
Visit the Complete Guide to Spring 2018 for the Spring Forecast, tips to survive it and much more.
The Great Lakes and the Maritimes did have a warm summer that year, but much of Canada had near normal or colder than normal summer temperatures.
The following year was another infamous Canadian winter as temperatures were well below normal from British Columbia to Quebec.
The following summer was warm across western Canada, but the remainder of Canada had near normal or colder than normal temperatures during the summer. If the idea that the previous winter can really foreshadow the upcoming summer pattern was true, then all of western and central Canada should be the same colour on the map below, but that is not the case.
While cold winters can be followed by a warm summer, for every example of that happening there is an example of the opposite occurring.
One of the keys to seasonal forecasting is correctly identifying the primary factors that will help to drive the weather pattern for the season. Two of the better known variables that can influence the character of a season are El Niño and La Niña. However, with El Niño and La Niña the nature of their influence on weather patterns is different in the winter than it is during the spring and summer. In addition, some years El Niño or La Niña can persist from winter to summer while other years they are in the process of reversing from one phase to the other or trending towards a neutral phase (neither El Niño and La Niña).
RELATED: What is El Niño?
There are other variables that can persist from season to season that can have a similar impact on each season. For example, a large region of warmer than normal ocean water temperatures in the North Pacific Ocean to the west of Canada (often called “the blob”) contributed to a rather persistent and strong ridge in the jet stream pattern over western North America during the winter of 2013-2014 and that was dominant pattern through much of 2015. As a result, mild winters in the west were followed by hot summers.
So, unfortunately forecasting the character of a season is not as simple as looking back at previous seasons. Each season presents a unique challenge with numerous factors that contribute to the character of the season. We are currently finalizing our analysis for our spring forecast and taking a preliminary look ahead to the summer. Please check back February 26 for the release of our spring forecast.